[mythtv-users] One problem channel

[Brian Wood]

On Sunday, October 03, 2010 08:12:24 am Marc Williams wrote:
>   I'm a fairly new Myth user in the US.  I've set up a separate backend
> and frontend to go along with my dual tuner HDHomeRun.  It all works
> quite well and am so far quite impressed.
> 
> But just in the past couple days something odd has happened to my ABC
> affiliate channel.  Even though the signal strength is at or close to
> 100%, the picture is all jerky and is not sync'ed at all (not even
> close) to the audio.  When I feed the signal directly to the TV it's
> fine so I don't think it's a bad signal.  I've bounced all devices and
> I've deleted and rescanned all the channels (about 25 of them) but the
> problem remains with just that one channel.
> 
> Any ideas or troubleshooting tips would be most welcome.  Thanks!

Just some ideas:

Make sure that when you check with your TV set you are using the exact same cable that feeds your HDHR, using the same 
splitters, cable, fittings etc.

See if the problem exists with both HDHR tuners.

Signal strength itself often means nothing, you could have multi-path problems resulting in plenty of signal, but it's 
unusable due to the multiple paths. It's the BER (bit error rate) or "symbol quality" that actually means something.

Are all your stations coming from the same transmitter site? If the ABC station is significantly closer or farther away, it 
might explain the different performance, though of course that probably hasn't changed in the past couple of days (though 
you never know).

Look for anything that has changed in the "past couple of days", a building going up, trees planted and the like. It's 
autumn, and leaves are falling, but that usually improves things.

An email to the station's engineering department (usually listed on their web site), asking (in a cordial manner of 
course) if anything has changed, couldn't hurt.

The above assumes you are receiving the channels off the air, if they are cable QAM then you might contact the cable 
company (and you would be extremely lucky to get 25 clear QAM channels).